Plagiaulacida

Order Multituberculata:
SUBORDER "PLAGIAULACIDA"

This funny named group of animals are extinct mammals. Multituberculates were among the most common furry critters of the Mesozoic, ('the age of the dinosaurs'). Plagiaulacids, (an informal suborder), are the most basal of these multis, and ranged from the Middle Jurassic to the Lower Cretaceous of the northern hemisphere.

In more detail: Kielan-Jaworowska and Hurum (2001) divides “Plagiaulacida” into three informal lineages, each of which seems to represent a natural group, (an ancestor and all its descendants). However, a firmer conclusion must await further evidence.

1. Allodontid line
Both allodontids and paulchoffatiids (below) were amongst the most basal of the plagiaulacids. The Allodontid line contains:
Family: Allodontidae
Two genera from the Upper Jurassic Morrison Formation[?] of North America.
Family: Zofiabaataridae
This family contains a single genus, Zofiabaatar, and is also from the Morrison Formation.
The affinities of a further Morrison Formation genus, Glirodon, are unclear, but it’s also within the Allodontid line.

2. Paulchoffatiid line
Some remains from the Middle Jurassic of England might belong within this group. Representatives are best known from the Upper Jurassic, (especially from Guimarota, Portugal), though some were still nibbling during the Lower Cretaceous.
Family: Paulchoffatiidae
The various genera can be visited on the family page. They're divided into two of subfamilies, plus a couple of harder to place individuals:
Subfamily Paulchoffatiinae:
Paulchoffatia and its nearest and dearest. This taxon contains nine genera.
Subfamily Kuehneodontinae:
Consists solely of the genus Kuehneodon, though there are half-a-dozen named species.
Other genera:
Galveodon and Sunnyodon are based on teeth from the Lower Cretaceous of Spain and England respectively.

Also referable to the paulchoffatiid line, (but not the family itself), are the following:
Family: Hahnodontidae:
Presently restricted to a single lower tooth from the Upper Cretaceous of Morocco, (Hahnodon).
Family: Pinheirodontidae:
Lower Cretaceous teeth from Iberia and England.

3. Plagiaulacid line
The members of this line are further derived then is the case with the other two lineages.
Family: Plagiaulacidae:
Upper Jurassic (North America) to Lower Cretaceous (Europe and Asia).
Plagiaulax, Bolodon, 'Ctenacodon' brentbaatar. The 'C.' requires renaming, whilst material from China has yet to be described, (state of play in 2001).
Family: Albionbaataridae:
Upper Jurassic to Lower Cretaceous of Europe and Asia, (China – undescribed, 2001). These were shrew-sized mini multis, with some similarities to the paulchoffis.
Family: Eobaataridae:
Eobaatarids display dental similarities with some of the Paracimexomys group, (Cimolodonta).
Upper Jurassic to Lower Cretaceous of Europe and Asia, (China – undescribed, 2001).
Sinobaatar was described after the study by Kielan-Jaworowska and Hurum (2001). It might be based on some of the Chinese material they mentioned as undescribed.

The Mongolian word ‘baatar’ is frequently employed in the nomenclature of multituberculates. This reflects the fact that many of the most complete fossils have been recovered from sites in Mongolia, though this more applies to members of the more derived Cimolodonta.

A couple of further genera possibly fit somewhere within “Plagiaulacida”. This has been tentatively proposed for Janumys of the Mid Cretaceous. Its contemporary, Ameribaatar, is of uncertain affinities. Both were first described late in 2001.

References: Hahn G & Hahn R (2000), Multituberculates from the Guimarota mine, p.97-107 in Martin T & Krebs B (eds), Guimarota - A Jurassic Ecosystem, Verlag Dr Friedrich Pfeil, München.
Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.

(This information has been derived from [1] (http://home.arcor.de/ktdykes/multis.htm) Multituberculata Cope, 1884. As that's my webpage, there are no issues of copyright. Trevor Dykes)